Evoked potentials

Visual evoked potentials (VEP):
Findings: The patient has a well-developed, reproducible response to alternating checkerboard patterns at 50 minutes and 30 minutes of arc. The latencies for P100 are as follows: OD = 103ms, OS = 112ms.

Impression: Visual evoked potentials are abnormal. The right optic nerve is normal. There is a significant conduction delay involving the left optic nerve.

Tibial and median evoked potentials (SSEP):
Findings: Upon stimulating either posterior tibial nerve, the patient has well-developed, reproducible responses at the expected levels.
The latencies are as follows: Popliteal response left 10.6, right 11.1. Lumbar response, left, 24.4; right, 23.1. Cortex, left, 41.5; right, 41.6.
Central conduction as represented by the interval between the lumbar response to cortical response: Left, 17.1; right, 18.5.

Impression: Normal posterior tibial nerve SSEPs. This test provides no evidence for conduction delay from the lower extremities to the cortex.